| Bsmt Limited | Information & communication | 2015 |
| Bsure Solutions Limited | Wholesale & retail | 2003 |
| Btdt Ltd | Information & communication | 2025 |
| Bubble Angels Ltd | Administrative & support | 2025 |
| Bubble Home Care Ltd | Public administration | 2026 |
| Buckingham Close (Hornchurch) Management Association Limited | Hospitality | 1974 |
| Buckingham Medical Technologies Ltd | Professional & scientific | 2013 |
| Buckton Properties Ltd | Real estate | 2023 |
| Budders Limited | Administrative & support | 2024 |
| Build Field Ltd | Construction | 2019 |
| Build Hub (South East) Limited | Information & communication | 2024 |
| Build Masters Hub Ltd | Construction | 2025 |
| Builder Projects Ltd | Construction | 2020 |
| Builders Construct Limited | Construction | 2026 |
| Building Control Services (Approved Inspectors) Limited | Professional & scientific | 2013 |
| Building Control Services Limited | Administrative & support | 2005 |
| Building Lives Project CIC | Health & social care | 2017 |
| Buildqo Ltd | Construction | 2026 |
| Built Resource Group Ltd | Construction | 2026 |
| Bulgarian Primary Secondary Schools Colleges/Bpssc/ CIC | Education | 2018 |
| Bulica Group Ltd | Construction | 2024 |
| Bulk Express Services Ltd | Transport & logistics | 2015 |
| Bull Properties Limited | Real estate | 2016 |
| Bulldog Digital Media Limited | Information & communication | 2012 |
| Bulldog Investments Holdings Limited | Professional & scientific | 2019 |
| Bullet Cleaning & Carpeting Limited | Administrative & support | 2014 |
| Bullet Cleaning Ltd | Administrative & support | 2011 |
| Bullman Interiors Ltd | Construction | 2022 |
| Bullseye Restoration Ltd | Construction | 2025 |
| Bullseye Services Limited | Construction | 2009 |
| Bumble & Berry Ltd | Professional & scientific | 2017 |
| Bumps, Babes & Tots Ltd. | Health & social care | 2013 |
| Bunciu Cleaning Ltd | Administrative & support | 2018 |
| Bungalow One Limited | Hospitality | 2021 |
| Burford and Co Properties Ltd | Real estate | 2020 |
| Burgas 90 Ltd | Hospitality | 2025 |
| Burgess Media Limited | Information & communication | 2023 |
| Burghley Boutique Glamping Limited | Hospitality | 2023 |
| Burl Brothers Transportation Ltd | Transport & logistics | 2021 |
| Burl Properties Ltd | Real estate | 2025 |
| Burner Hub Ltd | Wholesale & retail | 2025 |
| Burniston Bulk Limited | Transport & logistics | 2025 |
| Burntwood Gardens (Brentwood) Management Company Limited | Households | 2017 |
| Burrows Farming LLP | | 2022 |
| Bury Consultancy Ltd | Administrative & support | 2019 |
| Bushcade Holdings Limited | Professional & scientific | 2001 |
| Bushcade Limited | Construction | 1991 |
| Bushido Martial Arts Ltd | Other services | 2023 |
| Business Accountancy Limited | Professional & scientific | 2015 |
| Business and Financial Solutions Limited | Professional & scientific | 2005 |
| Business Friend Limited | Administrative & support | 2003 |
| Business Support Initiative Ltd | Administrative & support | 2013 |
| Butt Hatch Farm Limited | Agriculture & fishing | 1952 |
| Butter & Scotch Ltd | Manufacturing | 2019 |
| Buttercup Montessori Kindergarten Limited | Education | 2011 |
| Butterstone Holdings Ltd | Financial services | 2024 |
| Buttling Brothers Operations Limited | Real estate | 2024 |
| Buttling Brothers Services LLP | | 2026 |
| Butts Green 1363 Ltd | Agriculture & fishing | 2025 |
| Buvans Limited | Health & social care | 2016 |
| Buy Gone World Limited | Wholesale & retail | 2012 |
| Buya Investments Ltd | Real estate | 2025 |
| Buya Property Ltd | Real estate | 2024 |
| Buysend.Com Limited | Wholesale & retail | 2008 |
| Buzz Into Beekeeping Limited | Manufacturing | 2025 |
| Buzzlead AI Limited | Information & communication | 2023 |
| BVC Constructions Ltd | Construction | 2021 |
| BWD Enterprise Ltd | Real estate | 2025 |
| BXG Europe Engineering Ltd | Professional & scientific | 2025 |
| BY Brody Lane Ltd | Wholesale & retail | 2025 |
| BY the RIO Ltd | Real estate | 2025 |
| Bygone Marketing LLP | | 2004 |
| Byrne Building Services Ltd | Construction | 2021 |
| Byrne Future Investments Limited | Financial services | 2021 |
| Bytebond Ltd | Administrative & support | 2023 |
| Bytebrook Limited | Administrative & support | 2001 |
| Bytetonesteve Ltd | Information & communication | 2014 |
| C & B Vehicle Rentals Ltd | Administrative & support | 2026 |
| C & C Automotive Ltd | Wholesale & retail | 2013 |
| C & J Early Years Limited | Education | 2026 |
| C & K Recoveries Limited | Administrative & support | 2015 |
| C & M Roofing & Builders Ltd | Construction | 2005 |
| C & M Tramontini Limited | Financial services | 2000 |
| C & P Property Rentals Limited | Real estate | 2023 |
| C & S Nirvana Chartering LLP | | 2023 |
| C and C Contracting Limited | Administrative & support | 2022 |
| C Cosmetics Ltd | Health & social care | 2016 |
| C D Kent Limited | Professional & scientific | 2013 |
| C D Robinson Services Limited | Professional & scientific | 2023 |
| C G Electrical Essex Limited | Construction | 2023 |
| C J Cochrane Futures Limited | Administrative & support | 2002 |
| C J Computing Limited | Information & communication | 2005 |
| C M S (Essex) Limited | Construction | 2007 |
| C Pryde Ltd | Arts & recreation | 2020 |
| C Q Surfacing Limited | Construction | 2016 |
| C Sport Media Ltd | Professional & scientific | 2026 |
| C Thomas Tattoo Limited | Other services | 2023 |
| C&B Homes Ltd | Real estate | 2020 |
| C&L Crump Property Ltd | Real estate | 2026 |
| C&L Glass Ltd | Construction | 2012 |